GLACIAL HISTORY OF THE LITTLE ICE AGE IN KONGRESS VALLEY, SVALBARD: A STUDY OF LACUSTRINE SEDIMENT

Sediment cores from proglacial lakes can provide a record of glacial history and therefore past climate variations. This study involves analysis of a core from Lake Kongress, on the high-arctic archipelago of Svalbard. Characteristics of the core are examined in this study to address several major questions and objectives. During the Little Ice Age (LIA), a cold period between about the 14th and 19th centuries, did the Kongress Glacier grow large enough to contribute melt-water and sediment to Lake Kongress? What was the timing and extent of the LIA in Kongress Valley? Finally, does the core examined in this study record late 20th century warming?

Analyses of samples from the core and from fans feeding the lake include: stratigraphic description, X-ray diffraction, loss on ignition, and 137Cs and 210Pb dating. These analyses provide for three proxies of past glacial extent. X-ray diffraction provides a carbonate index for samples, which indicates sediment provenance and therefore provides a record of activity of the glacially-fed fan. LOI provides a measure of the weight percent organic matter of samples, which is used as an indicator of clastic sedimentation rate and, indirectly, glacial extent. Dating provides a measure of changes in sedimentation rate, as well as chronological control.

The results of this study provide for an overall characterization of the LIA in Kongress. There are two major culminations of LIA glaciation evident in the core. The first began around 1200-1240 A.D., with maximum ice extent occurring around 1300-1500 A.D. This period lasted until about 1610 A.D. A period of conditions too warm or dry for glacial advance pervaded from about 1610 to 1810 A.D. The maximum ice extent during the second culmination of the LIA occurred around 1770-1800 A.D. A secondary maximum probably occurred near the end of the second culmination of the LIA. Retreat from this event was happening between 1914 and 1936 A.D, which, in this study, defines the end of the LIA. There is also evidence in the lake core of increased productivity during the late 20th century, indicative of warming. Instrumental measurements of the water temperature of Kongress Lake support this finding.The chronology of the LIA in Kongress fits with other studies conducted on Svalbard, and provides for comparison to other locations in the Northern Hemisphere.